[secdir] secdir review of draft-ietf-dnsop-as112-dname-04

["Klaas Wierenga (kwiereng)" <[e-mail]>]

Hi,

I have reviewed this document as part of the security directorate's 
ongoing effort to review all IETF documents being processed by the 
IESG.  These comments were written primarily for the benefit of the 
security area directors.  Document editors and WG chairs should treat 
these comments just like any other last call comments.

I believe this document is "ready with issues."

The document describes adding and dropping of zones for AS112, the zone that is meant rot act as a sinkhole for reverse lookups for addresses that are for private-use only.

I think the document is clearly written and with my limited understanding of DNS it all seems to make sense from a technical point of view. 

What I am not so sure of however is the statement in the security considerations: 

"This document presents no known additional security concerns to the Internet.
For security considerations relating to AS112 service in general, see RFC6304bis]."

And in the introduction

"The AS112 project does not accommodate the addition and removal of
  DNS zones elegantly.  Since additional zones of definitively local
  significance are known to exist”

It appears to me that moving from a static list of well known ranges as defined in 6304bis to a dynamic adding and dropping of IP-address ranges that are "of definitively local
  significance” is prone to error, potentially leading to blackholing valid address space, either on purpose or by accident. I may show my ignorance here, but I feel that a discussions as to why that risk doesn’t exist is warranted. 

Hope this helps,

Klaas